Compressor



Dec. 25, 1951 c. 1.. DENSHAM 2,580,006

COMPRESSOR Filed April 1, 1949 4 Sheets-Sheet 1 L) Q k I nvenlor C fin Lane Denslunn a, mi 8104 Attorneys Dec. 25, 1951 c. L. DENSHAM 2,580,006

COMPRESSOR Filed April 1, 1949 v v 4 Sheets-Sheet 2 In venlor Attorneys Dec. 25, 1951 c. 1.. DENSHAM 2,580,006

COMPRESSOR Filed A'pril 1, 1949 Y 4 Sheets-Sheet 3 I I w i w e i I i I a \1\\ a I a Q [mm m I N m k Inventor 8/ 7 WuAEMMU eys Patented Dec. 25, 1951 COMPRESSOR Costin Lane Densham, Chaldon, England, as-

signer to Wade Engineering Limited Application April 1, 1949, Serial No. 84,897

In Great Britain April 7, 1948 The invention relates to a compressor-for elastic fluids of the kind having a pair of rotors arranged for rotation in opposite senses within a ported casing, each rotor having at least one recessed portion forming a rotating chamber for transferring fluid from an inlet port to an outlet port.

The most common type of elastic fluid compressor such as is used for internal combustion engine superchargers or compressors for the atmospheres in aircraft cabins is a blower of the Rootes type. In such compressors the elastic fluid is carried through the casing by a pair of rotors and it is impossible to provide compression within the casing since the effect of the moving rotors is merely to produce displacement of the fluid. Consequently the compression produced by such blowers is due to a throttle in the outlet passage.

Proposals have been made for blowers having rotors with sliding vanes on rotors working within elliptical casings so as to produce compression within the blower casing but such arrangements have not been satisfactory mechanically.

The object of the present invention is to produce a compressor having the mechanical advantages of the well-known Rootes type but in which it is possible to provide a variable compression within the casing.

In accordance with the invention, in a compressor as hereinbefore specified, the rotors are so formed and driven that a projecting part of one rotor progressively enters the recessed part of the other rotor during its movement from the inlet port towards the outletport so that the. gas within the rotating chamber 'iscompressed progressively as the chamber rotates and the chamber has an outlet port and means for varying the timing of the opening of the port so that a selected compression may be attained before the fluid can leave the rotating chamber.

Conveniently, at one end of each rotor there is provided a ported web, and a movable ported plate is interposed between the ported web and and an end wall of the casing to provide the necessary timing means.

In one form the periphery of each rotor may comprise one projecting lobe and one recess, the lobe and recess both having a part cylindrical surface and being connected by a portion contoured, to obey the earing law. A compressor having such rotors gives two compression impulses per revolution, 1. e. one impulse per rotor. Such a compressor can be constructed to give compression ratios of the order of 1, but where lower compression ratios are sufficient, rotors hav- 3 Claims. .(01. 230-138) ing two or more lobesmay be used, and the compressor gives four or more compression impulses per revolution.

The invention is further illustrated in the accompanyingdrawings in which: Fig. 1 is a perspective view of the compressor in accordance With the invention, Fig. 2 is a similar View with the casing partly dismantled, Fig. 3 is a longitudinal section of the compressor shown in Fig. 1, Fig. 4 is a section along the lines 4-4 of Fig. 3 and Fig. 5 is a similar section showing a modified shape of rotor.

Referring to Figs. 1 to 4, the compressor comprises a casing having a main body II] with inlet ports 20, 2| and. detachable end caps I I, I2 which are internally ducted to provide an outlet for gas compressed in the casing, the outlet gases being exhausted into a manifold I3. The detachable end caps II, I2 house bearings for shafts I 4, I5 on which are mounted rotors IS, IT. The shaft I5is extended at I5 to form a driving connection and within the end cap II are accommodated gear wheels I8, I9 which drive the shafts I4; I5 and rotors I0, I! in opposite rotational senses. Each rotor (see Fig. 4) has two lobes I6, I6 and I I, I1" between which are recesses. The lobes and recesses have part cylindrical surfaces of differing diameter which contact along the line where they intersect the axial plane of the shafts I l, I5. Inlet ports 20, 2| are provided midway of the side wall of the casing I 0 opposite the axes of the shafts I4, I5, respectively. At one end of the rotor I6 is fixed a web 24 having a port 25 the other rotor having at the other end a'similar web 26 with a port 21.

The end cap I I has an end wall 28 with a port 29 which communicate with a flanged outlet 30 to which the manifold I3 is bolted. Interposed between the end plate 24 on the rotor I6 and the end wall 28 is a rotatable plate 3I having a port 32. A similar rotatable plate 33 having a port 34 is carried in the other end cap I2, the plate 33 however being associated with the rotor H (see Figs. 3 and 4) In operation the two rotors I6, II are rotated in opposite directions as shown in Fig. 4 and it will be appreciated that in Fig. 4 the recess in the rotor I6 lying adjacent the inlet port 20 is full of air and the inlet port 20 is about to be closed by the lobe I6", while the corresponding recess in the rotor I1 is filling with air from inlet port 2!. The lobe IT on the rotor I! is entering the opposite recess in the rotor I6, and when the port 32 begins to overlap the port 25 (see Fig. 2) the gas in the recess will begin to discharge. Meanwhile,

the other lobe 16' on the rotor 16 will enter the corresponding recess in the rotor ll, the discharge of gas commencing when ports 21 and 34 overlap. By rotation of the plates 31 and 33 the timing of the opening of the ports can be varied, so varying the effective compression. Plates 3| and 33 are connected by links 22 and 23 to control means (not, shown), which may be. manual or automatic, e, afbarometric capsule, orja boost control.

It will be appreciated that in the form dcscribed and shown in Figs. 1-4 since each rotor has two recesses there are two compression" strokes per rotor per revolution.

Fig. shows a compressor with rotors, lfiand. i? each having a single lobe.

rotor per revolution and higher compressions are therefore obtainable in a compressor havin such rotors. Otherwise the construction and operation of the compressor is as described in connection with Figs. l'to 4.

"Though the primary and intended use of the apparatus is as a compressor, and it -has been de-'- scribed as such, it will be appreciated that a 'comcasing comprising side and end walls, said casing; having at least one'gas inlet passage in its side 1 wall and having an outlet passage in each end wall, a pair of rotors each having mutually interengageable lobes and recesses said recesses forming gas transfer chambers, gearing for causing the-rotors to rotate in opposite directions in such timed relationship that a lobe on one rotor enters a recess on the other rotor after said'recess has' passed the end of the inlet passage and before it reaches the end of the outlet passage whereby.

gases are compressed duringtheir transfer within said recess, each rotor having an integral ported web at one end, thewebbed ends of ithe'rotors being arranged at opposite ends of the casing, and thecasing having a rotatably'mountedported plateateach' end cooperatingwi'th the adjacent ported web of a rotor, and control means for adjusting the'position of each ported plate within the casing whereby the timingof the overlap of the'ports in said web and said plate may be adjusted.

2; A, compressor comprising in, combination a 15. With thisformbf" rotor there is only one compression. pulse, per;

casing having a body portion comprising a side wall with at least one gas inlet passage therein, an end cap attached to each end of the casing, each end cap having a gas outlet passage therein and secured to said body portion, a pair of rotors of identical non-circular and inter-engaging section mounted for rotation in opposite directions in said'casingand mounted-in saidend caps and providingjr-ccessels, between their, inter-engaging portions whereby gas is transferred from the inlet passage to the outlet passage and compressed during its transfer in said recesses, one ported web'i'nounted for rotation with each rotor at the end thereof, saidwebs being at opposite ends of tl'flel'casingjadjacentthe respective end caps, a ported plate each end cap contacting the adjacentporte'd web, said plate being rotatable within'the'end-cap, and control means for controlling the angular position of said plates to adjust the manger overlap of the ports in said webs and Flaw 3i compressor comprising a casing with par alle'l inter-communicating cylindrical bores closed by end'caps, a pair of oppositely rotatable lobed inter meshing impeller rotors insaid bores, said rotors each having one ported end plate secured.

thereto adjacentopposite ends of the casing, two inlet portsrespectively opening into the impllerswept side wallsjo'f Said bores to admit fluid to be compressed, outlet ports arranged in the end" caps, one; adjacent each ported end plate to re-f lease fluid which has been' compressed, and a roftatable ported timing plate interposed between each of said outlet portsj'and'the adjacent ported platoon the'rotor to vary the compression with in said casing.

' CQSTIN LANEDENSHAM,

REFERENQES CITED The followingre ierences are of record in the fileofthis liatenti.

UNITED STATES PATENTS 

